feat(docker): Gracefully reload Caddy configuration

CaddyManager.Contracts/Docker/CaddyReloadResponse.cs

@@ -0,0 +1,17 @@
+namespace CaddyManager.Contracts.Docker;
+
+/// <summary>
+/// Result of a graceful Caddy configuration reload
+/// </summary>
+public class CaddyReloadResponse
+{
+    /// <summary>
+    /// Indicates whether Caddy accepted and applied the configuration
+    /// </summary>
+    public bool Success { get; set; }
+
+    /// <summary>
+    /// Output from Caddy when the reload failed, typically the configuration validation error
+    /// </summary>
+    public string Message { get; set; } = string.Empty;
+}

CaddyManager.Contracts/Docker/IDockerService.cs

@@ -10,4 +10,11 @@ public interface IDockerService
     /// </summary>
     /// <returns></returns>
     Task RestartCaddyContainerAsync();
+
+    /// <summary>
+    /// Method to gracefully reload the Caddy configuration without restarting the container. Caddy validates the
+    /// configuration before applying it, so a broken configuration leaves the running one untouched.
+    /// </summary>
+    /// <returns>Whether the reload succeeded, along with Caddy's output when it did not</returns>
+    Task<CaddyReloadResponse> ReloadCaddyContainerAsync();
 }